Linux 配置SSH互信

最简单的一种形式配置主机间的互信，假设有两台主机A、B，A作为客户端，B作为目标机，可以做如下配置：

在A客户端设置：

➜  ~ ssh-keygen -t rsa -b 2048 -f my_key
Generating public/private rsa key pair.
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in my_key
Your public key has been saved in my_key.pub
The key fingerprint is:
SHA256:Ls8NyhrXtrCZQ2lNU+h4E7MPpWu4BjtSo15ZOPSRIo0 xxx@xxxx.local
The key's randomart image is:
+---[RSA 2048]----+
|         .       |
|   o   .+ o      |
|  E + oo B       |
|   o +..X        |
|    o o*S*       |
|    ++=o+ .      |
|   o+*+o=        |
|  o.o++@ +       |
| ....+*.+ .      |
+----[SHA256]-----+
➜  ~

将公钥分发到主机B

ssh-copy-id root@192.168.86.129

确保目标主机上的 ~/.ssh/authorized_keys 文件的权限为 600

chmod 600 ~/.ssh/authorized_keys

设置 SSH 服务

vim /etc/ssh/sshd_config

修改如下

PubkeyAuthentication yes
# The default is to check both .ssh/authorized_keys and .ssh/authorized_keys2
# but this is overridden so installations will only check .ssh/authorized_keys
AuthorizedKeysFile      .ssh/authorized_keys

重启ssh服务

systemctl restart sshd

验证免登录

➜  ~ ssh root@192.168.86.129
Activate the web console with: systemctl enable --now cockpit.socketLast login: Sun Dec 29 21:19:23 2024 from 192.168.86.1
[root@localhost ~]#

这是最基础，最简单的用法。

当然更加规范的用法是在互信机器之外为用户（注意，是为用户，不是为某个机器）生成密钥，比如说密钥中心等，这里就不再展开说了